White light scanning is an optical three dimensional geometric measuring system which is based on the principle of triangulation. To create the object surface digital model, a structured white light source is used to project controlled fringe patterns on the object. These fringe patterns are recorded as high resolution images with twin digital cameras. The data collected by theses cameras are used to create a highly accurate and precise image of the object's entire surface. While contact measurement systems and devices provide only a partial set of landmark measurements on the object, white light three dimensional scanning captures the entire surface. The scanner is capable of picking up tens of thousands of data points per second and the highly automated process insures consistency and quality.
This highly accurate complete three dimensional digital model is then compared to the object's original CAD model and any geometric variation between these two is vividly shown in “color plots” with adjustable tolerance ranges as well as complete tables of measurement and deviation numbers. The increased ease of interpretation and understanding from these color plot reports is one of the key advantages of this method of geometric measurement and quality analysis. This process enables quick and accurate product inspection, such as prior to production implementation, or after periods of extended use and or product remanufacture and so on. The inspection performs a comparative analysis of the CAD model to the actual product thereby identifying the imperfections. In addition, because white light three dimensional scanning is non destructive analysis and encompasses the entire object it is possible to reverse engineer the object based on the data collected during the scanning process. This enables the remanufacture of parts for which there is no CAD data. The white light scanning is an important tool in the design and development of products, the tooling and fixturing for manufacture and the inspection of the product at any point in its life cycle. It has applicability in a large number of manufacturing enterprises such as the aerospace, automotive, and medical industries, for example.
The white light three dimensional scanning process will encounter problems where the surfaces to be scanned are reflective, refractive or the object is translucent or transparent. Conventionally an object may be coated with spray paint or with a powder like material to enhance surface characteristics of an object. However, while these techniques may provide assistance in the white scanning process, the result in a non-uniform surface finish which destroys the ability to use the white light scanning process to provide accurate and consistent three dimensional data collection. The system embodying the present invention is able to offer advantage including improved accuracy, reduced cost and increased usability over the conventional technologies.